Gas turbine ducted fan engine

ABSTRACT

A GAS TURBINE DUCTED FAN ENGINE HAS A FAN HOUSED IN A FAN DUCT. A PORTION OF THE FAN DUCT IS CONSTITUTED BY TWO SPACED APART WALLS, ONE WALL CONSISTING OF MEMBERS EACH OF WHICH HAS A FLANGE WHICH EXTENDS TO THE OTHER WALL AND IS ATTACHED THERETO.

March 2, 1971 J. o. MORTLOCK 3,566,606

GAS TURBINE DUCTED FAN ENGINE Filed May 16, 1969 Inventor J MEs Osrwu fionrwcK 644%, 944i [24441 14 ttorneys United States Patent Oflice 3,566,606 Patented Mar. 2, 1971 3,566,606 GAS TURBINE DUCTED FAN ENGINE James Qswald Mortlock, Derby, England, assignor to Rolls-Royce Limited, Derby, England Filed May 16, 1969, Ser. No. 825,308 Claims priority, application Great Britain, May 28, 1968, 25,484/68 Int. Cl. F02k 3/04; F04d 29/58 U.S. Cl. 60-226 10 Claims ABSTRACT F THE DISCLOSURE A gas turbine ducted fan engine has a fan housed in a fan duct. A portion of the fan duct is constituted by two spaced apart walls, one wall consisting of members each of which has a flange which extends to the other wall and is attached thereto.

This invention relates to gas turbine ducted fan engines.

According to the present invention there is provided a gas turbine ducted fan engine having an annular duct, a fan housed in the annular duct, two spaced apart walls constituting at least a portion of the annular duct, one of said spaced apart walls consisting of a plurality of members, each of which has at least one integral flange extending to at least the other wall and is secured thereto, a step being formed in each of said members, said step being adapted to receive a part of the next adjacent member.

A foot may be provided adjacent the end of each flange, said foot being secured to the other wall.

Alternatively, said flange may be U-shaped having a foot adjacent the end thereof, said foot being attached to the next adjacent member.

Said walls may be made of metal, said flanges being secured to said other wall by welding.

The spaces between the two walls may be adapted to receive hot air.

Preferably said portion of the annular duct is upstream of the fan.

According to another aspect of the present invention, there is provided a gas turbine ducted fan engine having an annular duct, a fan housed in the annular duct, two spaced apart walls constituting a portion of the annular duct, one of said spaced apart walls consisting of a plurality of members, each of which has at least one integral U-shaped flange extending to at least the other wall and is secured thereto, a foot being provided adjacent the end of each flange, said foot being attached to the next adjacent member.

A step preferably is formed in each of said members, said step being adapted to receive a part of the next adjacent member.

The invention is illustrated, merely by way of example, in the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of a gas turbine front fan engine provided with a fan shroud, partly shown in section, according to the present invention,

FIG. 2 is a broken-away view on a larger scale of part of the structure shown in FIG. 1,

FIG. 3 is a section taken on the line 3-3 of FIG. 2, and

FIG. 4 is a sectional view of an alternative embodiment of the present invention.

In FIG. 1 there is shown a front fan gas turbine engine having an engine casing 11 within which there are mounted, in flow series, low and high pressure compressors 12, combustion equipment 13 and high and low pressure turbines 14, the turbine exhaust gases being directed to atmosphere through an exhaust duct 15.

Mounted concentrically about the engine casing 11, and arranged at the upstream end of the latter, is an outer casing 16 which is double-walled and forms the fan shroud of a front fan 17. The downstream end of the casing 16 is supported from the engine casing 11 by means of a plurality of angularly spaced apart struts (not shown).

The casing 16 comprises an inner metal wall 20 and an outer metal wall 21. The two walls may be integral with each other as shown or seam-welded together at the leading edge of the casing 16. The inner wall 20 has a portion 22 which is double-walled and has axially extending cavities 23 therethrough.

The portion 22 is shown in FIG. 3 and it will be seen that there is a wall 24 which consists of a plurality of overlapping members or sections 25. Each section 25 has at its downstream end 26 a step 27 and a radially inwardly extending flange 28 provided with a foot 31. The upstream end 32 of each section 25 engages the step 27 of the adjacent section, and the two may be attached together by welding or the like. The feet 31 are also welded to the inner wall 20, thus making a strong double-walled structure having the axially extending cavities 23 therethrough.

FIG. 4 shows an alternative embodiment of the present invention which is similar to that shown in FIG. 3 and so will not be described in detail, like parts having been given like reference numerals. The flange 28 is U-shaped and is welded to the inner wall 20 at 43. The flange 28 is provided with a foot 44 which is secured by welding or the like to the next adjacent section 25. Thus the flange forms a further axially extending cavity between the inner wall 20 and each section 25.

The portion 22 of the inner wall is positioned upstream of the tip of the fan 17. The walls 20 and 21 are kept apart by two spaced apart radially extending annular members 33, 34. These annular members are welded to the outer wall 21 and portion 22 by means of L-shaped brackets 35. Both annular members 33, 34 have apertures 36, 37 respectively provided therethrough. Sandwiched between the L-shaped bracket 35 and the downstream end of the portion 22 is provided a frusto-conical member 40 which is welded to a continuation 20a of the inner wall 20.

In operation hot air is fed, by means not shown, to the downstream end of the casing 16. The hot air passes through apertures 36, 37 in annular members 33, 34 and impinges on the leading edge of the fan shroud. The hot air then passes through the cavities 23 and back into the fan duct via a cavity 41 formed between the portion 22 and the frusto-conical member 40. This passage of hot air is designed to perform a de-icing or de-frosting function of the casing 16.

The casing 16 is shown in FIG. 1 to be cylindrical, however, it may be frusto-conical and it will be appreciated that to accommodate the increase in diameter of the downstream end of the casing the overlap between the ends 32 of the sections 25 and the grooves 27 may be decreased with increased diameter of the casing 16.

I claim:

1. A gas turbine ducted fan engine having an annular duct, a fan housed in the annular duct, two spaced apart walls constituting at least a portion of the annular duct, one of said spaced apart walls consisting of a plurality of members each of which has at least one integral flange extending to at least the other wall and is secured thereto, a step being formed in each of said members, said step being adapted to receive a part of the next adjacent member.

2. A gas turbine ducted fan engine as claimed in claim 1 in which a foot is provided adjacent the end of each flange, said foot being secured to the other wall.

3. A gas turbine ducted fan engine as claimed in claim 1 in which said walls are made of metal, said flanges being secured to said other wall by welding.

4. A gas turbine ducted fan engine as claimed in claim 1 in which the spaces between the two walls are adapted to receive hot air.

5. A gas turbine ducted fan engine as claimed in claim 1 in which said portion of the annular du t is upstream of the fan.

6. A gas turbine ducted fan engine having an annular duct, a fan housed in the annular duct, two spaced apart walls constituting a portion of the annular duct, one of said spaced apart walls consisting of a plurality of members each of which has at least one integral U-shaped flange extending to at least the other wall and is secured thereto, a foot being provided adjacent the end of each flange, said foot being attached to the neXt adjacent memher.

7. A gas turbine ducted fan engine as claimed in claim 6 in which a step is formed in each of said members, said step being adapted to receive a part of the next adjacent member.

8. A gas turbine ducted fan engine as claimed in claim 6 in which said walls are made of metal, said flanges being secured to said other wall by welding.

9. A gas turbine ducted fan engine as claimed in claim 6 in which the spaces between the two walls are adapted to receive hot air.

10. A gas turbine ducted fan engine as claimed in claim 6 in which said portion of the annular duct is upstream of the fan.

References Cited UNITED STATES PATENTS 2,556,736 6/1951 Palmatier 60-3909 2,594,118 4/ 1953 Boyd 60-39.09

2,827,760 3/1958 Marchant 6039.09

2,940,692 6/1960 Kerry 60-262 FOREIGN PATENTS 920,887 3/ 1963 Great Britain 60226 DOUGLAS HART, Primary Examiner US. Cl. X.R. 

